Add user_landing view
###New view: User Landing
- Adds a new view, access when Django determines a path structure matching /user//.
- view attempts to match string to a UserIdentifier in database and renders differently depending on if user is found or not (tested okay 12.10.20)
###Tweaked View: Generate Codephrase
- now gives 2 buttons - generate a new codephrase, or login with existing codephrase.